1. Field of the Invention
This invention relates to a fluid control circuit, and more particularly, a fluid control circuit for operating a press having a ram used for punching or bending metals, plastics, or the like.
2. Description of the Prior Art
Heretofore, presses were manually operated by an operator, who engaged a clutch connected to the main drive of the press to cycle the press. The position of the press ram had to be monitored visually by the operator at all times. If a malfunction occurred, the press would have to be stopped by the operator by disconnecting the drive which required releasing the clutch. The reaction time involved, assuming the operator could visually see the malfunctioning of the press, was such that the drive often was not disengaged in time to either preserve the work piece or the press mechanism itself. In some cases, injury to the operator resulted because of the malfunction.
As distinguished from the prior art, the present invention completely automates the press cycle once it is placed in operation by an operator. The position of the press ram is monitored at all times by the control circuit of the invention so that upon sensing a malfunction, the press will automatically shut down until the malfunction is corrected. If no malfunction occurs, the press completes its normal cycle without the operator having to visually monitor the operation. The circuit prevents the cycle from repeating unless the operator releases and redepresses one of the "cycle" switches, or switch pairs, as provided.